[Effects of Different Aeration Treatments on Bacterial Diversity, Metabolic Activity, and Function in Constructed Wetlands].

Bacteria play a key role in the removal of pollutants and nutrients in constructed wetlands. DNA and RNA high-throughput sequencing was used to investigate the diversity, metabolic activity, and function of bacteria in aquaculture wastewater and in constructed wetlands treated by different aeration levels. The results revealed that:① a total of 4042 operational taxonomic units (OTUs) were detected in aquaculture wastewater and constructed wetland treatment groups. α-Proteobacteria, γ-Proteobacteria, and Bacteroidia were the most diverse groups, and the constructed wetlands aeration treatment increased the bacterial diversity to a variable extent; ② α-Proteobacteria, γ-Proteobacteria, Bacteroidia, and Actinobacteria were the dominant groups both in the DNA and RNA sequencing results, and the metabolic activities of these four groups were significantly affected by the concentration of total nitrogen (TN) and nitrate nitrogen (NO3--N) in our study. ③ According to the FAPROTAX database, 56 bacterial functional groups were detected in our study, mainly including:chemoheterotrophy, aerobic chemoheterotrophy, fermentation, intracellular parasites, dark hydrogen oxidation, phototrophy, photoheterotrophy, and nitrate reduction. Functions related to the nitrogen cycle were observed in the results of function annotation, suggesting the important role of bacterial communities in the removal of nitrogen nutrients in constructed wetlands. These results will improve the understanding of bacterial community structures and functions during nutrient removal in aerated constructed wetlands.

Valproic acid exhibits biphasic effects on apoptotic cell death of activated lymphocytes through differential modulation of multiple signaling pathways.

Valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, possesses potent anti-tumor activity against a variety of malignant cells. However, its action on lymphocytes and the underlying mechanism are not completely understood. In this study, we aimed to analyze the effects of VPA on the proliferation, activation, and apoptosis of murine lymphocytes activated with concanavalin A (ConA). Our results showed that VPA inhibited the proliferation of ConA-activated lymphocytes in a dose-dependent manner. Low-dose VPA (≤ 1.1 mM) enhanced CD69 expression on the activated lymphocytes, whereas at high doses (≥ 3.3 mM) it decreased CD69 expression. Furthermore, VPA reduced activation-induced apoptotic cell death at low doses, but at high doses it promoted apoptotic cell death of activated lymphocytes dramatically. It was found that the Bax/Bcl-2 ratio and phosphorylation of histone H2A.X was decreased at low doses of VPA but was increased at high doses. The phosphorylation of STAT3 was also differentially regulated by different doses of VPA. VPA, at 5 mM induced the phosphorylation of p38 but not JNK and extracellular signal-regulated kinase (ERK)1/2. In addition, VPA induced a dose-dependent increase in the acetylation of histone H3. These results demonstrate that VPA exhibits dose-dependent biphasic effect on apoptosis of activated lymphocytes probably through differential modulation of several apoptosis-related signaling pathways.